Jenson Button has been told by Williams that they will not be "waiting around" for him to make up his mind on his future in Formula One.
Williams are keen to pursue a romantic move for Button, which would see the 2009 world champion return to the team with whom he started his grand prix career.
Button, 36, is out of contract with McLaren at the end of the season, but the British team have already announced they will not make a decision on their driver pairing for 2017 until September at the earliest.
Fernando Alonso has one more year to run on his current deal, while reserve driver Stoffel Vandoorne is waiting in the wings should McLaren terminate their seven-season relationship with Button.
In such a scenario, it is understood that Williams would be prepared to prolong Button's career into an 18th successive campaign.
But as Formula One heads for its summer shutdown, deputy team principal Claire Williams, speaking to Press Association Sport, said: "We will own our driver line-up decision, and I am not sat here waiting for (McLaren chairman) Ron Dennis to make his decision or for Jenson to make his decision.
"It it is not about what other people are doing. I am not going to be waiting around because that is just not the right mentality for a team like ours to have.
"It would be a great story, but he has to make the right choice for him, and we have to make the right choice for the team."
Felipe Massa's expected departure from Williams at the end of the season will free up some money, but doubts remain as to whether the Grove-based constructor will be able to afford Button. The Englishman currently earns around £12million a year.
Button's commercial appeal however, will also be seen as a huge attraction to Williams as they pursue sponsorship for 2017.
"He started his career here, but more importantly Jenson is a great driver, and he has still got a lot of fight left in him," Williams added.
"He is a great talent in the car, but also outside of the car and we need a driver like him. That is not to say our focus is purely on Jenson.
"When I talk about the criteria that we are looking at, it is the talent in the cockpit, the intelligence to feed back to the engineers, and for us, as an independent team, the commercial factors are going to play a part in the decision-making process too. You can't have an unknown driver in your car. It is just not going to work."
A move back to Williams could see Button link up with Valtteri Bottas, who the British constructor are keen to retain for a fifth successive season.
But another driver mooted to join is Force India's Sergio Perez. The Mexican, who has delivered a number of impressive displays this season, is also backed by Carlos Slim, one of the world's richest men, and would bring a wealth of money to the British team.
"Sergio has done a great job this year, he is an intelligent driver, and of course he is going to be someone we are looking at," Williams, who added that an announcement on their line-up for 2017 won't be made until the latter part of the campaign, said.
"I have only met him briefly on the odd occasion. He is very charming. He is very eloquent, so commercially he would be strong for any team. Of course he is going to be someone you'd consider if he is available."
Source: PA
